Sample 60526
60526 – 8.4 grams Impact Melt (KREEP)
Section titled “60526 – 8.4 grams Impact Melt (KREEP)”
Figure 1: The portait of KREEP. Sample is 2 cm across. S72-46332
Introduction
Section titled “Introduction”60526 is a dense, aphanitic, coherent rock fragment (figure 1). It has a high rare-earth-element and major element content characteristic of KREEP (Meyer 1974). It was collected as a rake sample – see section on 60501.
Petrography
Section titled “Petrography”According to Warner et al. (1976), the thin section of 60526 has a poikilitic texture with a matrix of low-Ca pyroxene and ilmenite oikocrysts surrounding small chadocrysts of augite, olivine and plagioclase. Armalcolite is reported.
High Ni content of metallic iron grains and relatively high Ir and Au bulk content indicate that this is an impact melt rather than a primary KREEP basalt.
60626 differs from 62235 etc, in that it does not seem to have relict xenoliths of plagioclase or lithic fragments.
Chemistry
Section titled “Chemistry”Warner et al. (1976) and McKinely et al. (1983) reported major element analysis. Korotev (1994) apparently analyzed 60526 and presented the data as “1M” (table).
Radiogenic age dating
Section titled “Radiogenic age dating”None
Processing
Section titled “Processing”There is only one thin section. A portion (,6) was made into a powder for fused bead analysis (unpublished).
Table 1. Chemical composition of 60526.
| weight | reference Warner76 | Korotev94 1M | ||
|---|---|---|---|---|
| SiO2 % TiO2 Al2O3 FeO | 47.5 1.4 17.4 8.9 | (a) (a) (a) | (a) 9.7 | (b) |
| MnO MgO | 0.09 13.5 | (a) (a) | ||
| CaO Na2O K2O P2O5 S % sum | 10.8 0.71 0.45 0.44 | (a) (a) | (a) 10.8 (a) 0.62 | (b) (b) |
| Sc ppm V | 14.6 | (b) | ||
| Cr Co Ni Cu Zn Ga Ge ppb As | 1163 | (a) 1520 63.9 1090 | (b) (b) (b) | |
| Se Rb Sr Y | 11.4 187 | (b) (b) | ||
| Zr Nb | 740 | (b) | ||
| Mo Ru Rh Pd ppb Ag ppb Cd ppb In ppb Sn ppb Sb ppb Te ppb | ||||
| Cs ppm Ba La Ce | 0.52 489 49.6 129 | (b) (b) (b) (b) | ||
| Pr Nd Sm Eu | 78 22.5 1.97 | (b) (b) (b) | ||
| Gd Tb Dy Ho Er | 4.51 | (b) | ||
| Tm Yb Lu Hf Ta W ppb Re ppb | 15.4 2.07 17.3 1.93 | (b) (b) (b) (b) | ||
| Os ppb Ir ppb Pt ppb | 21 | (b) | ||
| Au ppb Th ppm U ppm | 25 8.1 2.13 | (b) (b) (b) |
Figure 2: Thin section photo of 60526 (from Warner et al. 1976). 2 mm across
Figure 3: Composition of olivine and pyroxene in 60526 (Warner et al. 1976).
Figure 4: Processing photo of KREEP. Scale is metric with half mm ticks. S78-27394
References for 60526
Section titled “References for 60526”Butler P. (1972a) Lunar Sample Information Catalog Apollo 16. Lunar Receiving Laboratory. MSC 03210 Curator’s Catalog. pp. 370.
Korotev R.L. (1994) Compositional variation in Apollo 16 impact melt breccias and inferences for the geology and bombardment history of the central highlands of the Moon. Geochim. Cosmochim. Acta 58, 3931-3969.
LSPET (1973b) The Apollo 16 lunar samples: Petrographic and chemical description. Science 179, 23-34.
LSPET (1972c) Preliminary examination of lunar samples. In Apollo 16 Preliminary Science Report. NASA SP-315, 7-1—7-58.
McKinley J.P., Taylor G.J., Keil K., Ma M.-S. and Schmitt R.A. (1984) Apollo 16: Impact sheets, contrasting nature of the Cayley Plains and Descartes Mountains, and geologic history. Proc. 14th Lunar Planet. Sci. Conf. in J. Geophys. Res. 89, B513-B524.
Meyer C. (1977) Petrology, mineralogy and chemistry of KREEP basalt. Physics and Chemistry of the Earth 10, 239-260. (Ahrens and Runcorn, eds)
Ryder G. and Norman M.D. (1980) Catalog of Apollo 16 rocks (3 vol.). Curator’s Office pub. #52, JSC #16904
Warner R.D., Dowty E., Prinz M., Conrad G.H., Nehru C.E. and Keil K. (1976c) Catalog of Apollo 16 rake samples from the LM area and station 5. Spec. Publ. #13, UNM Institute of Meteoritics, Albuquerque. 87 pp.